Hello all. Noob here, so please don't run me over quite yet!

I purchased a stock 98 Civic EX about 5000 miles ago, with 60K miles on it. It had a major tune up at 58K. It seems to run ok, idles fine, etc. But a good deal of the time, when either accelerating or maintaining speed, it periodically runs a little bit roughly. I don't know if I'd call the symptom sputtering, but it does not operate completely smoothly.

The dealership I bought it from says they can't find a problem. They say it seems to run good for them. They mentioned that Civics have a tendency to "loke" (a term they gave me for jerky acceleration when climbing hills, engine under load, etc.) I previously owned a 91 civic, and the two drive about the same. I know the "loking" feeling their talking about, and my 91 did "loke". But otherwise my 91 ran nice and smooth despite its 160K engine.

I suspect maybe it could be either spark plugs, or a bad vacuum line (based on an experience with an S10). But in all honesty, I don't know much about what I'm talking about, so am reaching out to the experienced for help.

Any advice?

 

well, not sure what to tell you, but to ckeck if all of the spark plugs work correctly do the following:

1. Put the car in park and start it.

2. Rev the engine, and let go of the gas right away. You will feel the vibrations occasionally if the plugs or wires are bad. If you got a tachometer, your arrow should go down to about 700RPM and stay stable - if it doesn't you got plugs or wires

If it's not the plugs, try cleaning your TB. The dirt in there might prevent the TB door from closing completely.

Also, I think that vacuum leaks are only relavant to carbeurated cars

 

I don't know if this is whats happening to you but when I'm in second gear and let go of the gas, the car will tend to loke (rough ride, not smooth acceleration at low rpm) and e****ially when you repress on the gas. Thats probly what the mechanics are reffering to but if your civic does worst than that, it might just me some parts that are bad.

 

When I rev the car, it drops and idles smoothly, so I don't guess it's the spark plugs.

The car does do the normal loking, which is a rhythmic bouncing effect. The problem I'm facing is not rhythmic. It acts like it loses power for a fraction of a second, and may happen multiple times in a second, making a slight jerky feeling. If I didn't feel atuned to the feel of the car, I might think I was running over small bumps in the road. It happens in multiple gears, but the higher the gear, the less it is felt.

I spoke with a local auto parts store. They said if it was a vacuum hose or plugs, the computer would sense it and send a code. They mentioned a fuel filter as a try, but I thought if the filter was clogged, it was clogged and the vehicle would pretty much just sputter out. Had that happen on an old truck.

Any other ideas?

 

at 65k, its probably not the fuel filter, but its not a bad idea to change it out. as for vacuum, its probably not, as it would mess up your idle as well. i cant really put my finger on what your problem is, but it might not be a bad idea to do a compression test. this sounds a little like a VERY small head gasket leak. and i assume the major service included new plugs and wires, and cap and rotor, right?

 

I bought the car at 61K, and it had its tuneup done at 58K. I assume it got the standard 60K stuff done.

How would I go about getting a compression test done? And how much might I be looking at to do it? Wouldn't a leak like this send a signal to the computer?

BTW, it was a nice cool, dry day here in Florida. The car seemed to like it quite a bit, as it was running nice and smooth. Seemed to have a bit more pep too. I don't know what I'm talking about, but is it possible that it's not tuned for my area (Tallahassee, FL)? I understand the previous owner lived in Miami. Is it still true that cars need tuning for elevation, etc., or does the computer automatically handle that now?

 

well, i dont know how much it would cost to have one done, but a haynes manual runs about 15 bucks, a 12mm wrench should be less than a couple bucks, and a compression tester can be had for 15-30 bucks. so all together the whole thing will cost less to do it yourself than half an hour with a mechanic. and most have a minimum time of an hour. so if you have any mechanical know-how, get the tester and manual, and do it yourself. the manual tells you how to do it step by step.

 

Boy, sacicons, you're fast. I was editing my last post, and in between, you posted a response. Thank you. Please read the previous post again, as it has more stuff.

Also, if it's that cheap to do it myself, I might consider it. I tried to replace my radiator in my 91 Civic, but ended up having to get a mechanic to help. I was amazed at how easy he made it look, when he basically shoved the entire engine backwards on its mounts with one hand and inserted the new radiator with the other hand! Took a lot more strength than I could muster!

 

yeah, it could be the ecu. unplug the fuse under the hood that says something like ecm or ecu. then let it sit for at least 20-30 minutes, overnight is best, just to be sure. then plug it back in and start the car and let it idle with no load on it for about five minutes. that should allow time for it to readjust to the new settings.

 

I'll give that a shot tomorrow and let you know how it goes. Wouldn't it be nice if it was that simple?